| Message ID | 20170728133657.5525-1-berrange@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jul 28, 2017 at 02:36:57PM +0100, Daniel P. Berrange wrote: > The simpletrace compatibility code for systemtap creates a > function and some global variables for mapping to event ID > numbers. We generate multiple -simpletrace.stp files though, > one per target and systemtap considers functions & variables > to be globally scoped, not per file. So if trying to use the > simpletrace compat probes, systemtap will complain: > > # stap -e 'probe qemu.system.arm.simpletrace.visit_type_str { print( "hello")}' > semantic error: conflicting global variables: identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-aarch64-simpletrace.stp:3:8 > source: global event_name_to_id_map > ^ > identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:3:8 > source: global event_name_to_id_map > ^ > > WARNING: cross-file global variable reference to identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:3:8 from: identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-aarch64-simpletrace.stp:8:21 > source: if (!([name] in event_name_to_id_map)) { > ^ > WARNING: cross-file global variable reference to identifier 'event_next_id' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:4:8 from: identifier 'event_next_id' at :9:38 > source: event_name_to_id_map[name] = event_next_id > ^ > > We already have a string used to prefix probe names, so just > replace '.' with '_' to get a function / variable name prefix > > Signed-off-by: Daniel P. Berrange <berrange@redhat.com> > --- > scripts/tracetool/format/simpletrace_stap.py | 29 ++++++++++++++++++---------- > 1 file changed, 19 insertions(+), 10 deletions(-) Thanks, applied to my tracing tree: https://github.com/stefanha/qemu/commits/tracing Stefan
diff --git a/scripts/tracetool/format/simpletrace_stap.py b/scripts/tracetool/format/simpletrace_stap.py index c35e662e00..144b704bcd 100644 --- a/scripts/tracetool/format/simpletrace_stap.py +++ b/scripts/tracetool/format/simpletrace_stap.py @@ -18,29 +18,37 @@ from tracetool.backend.dtrace import binary, probeprefix from tracetool.backend.simple import is_string from tracetool.format.stap import stap_escape +def global_var_name(name): + return probeprefix().replace(".", "_") + "_" + name def generate(events, backend, group): + id_map = global_var_name("event_name_to_id_map") + next_id = global_var_name("event_next_id") + map_func = global_var_name("simple_trace_map_event") out('/* This file is autogenerated by tracetool, do not edit. */', '', - 'global event_name_to_id_map', - 'global event_next_id', - 'function simple_trace_map_event(name)', + 'global %(id_map)s', + 'global %(next_id)s', + 'function %(map_func)s(name)', '', '{', - ' if (!([name] in event_name_to_id_map)) {', - ' event_name_to_id_map[name] = event_next_id', + ' if (!([name] in %(id_map)s)) {', + ' %(id_map)s[name] = %(next_id)s', ' name_len = strlen(name)', ' printf("%%8b%%8b%%4b%%.*s", 0, ', - ' event_next_id, name_len, name_len, name)', - ' event_next_id = event_next_id + 1', + ' %(next_id)s, name_len, name_len, name)', + ' %(next_id)s = %(next_id)s + 1', ' }', - ' return event_name_to_id_map[name]', + ' return %(id_map)s[name]', '}', 'probe begin', '{', ' printf("%%8b%%8b%%8b", 0xffffffffffffffff, 0xf2b177cb0aa429b4, 4)', '}', - '') + '', + id_map=id_map, + next_id=next_id, + map_func=map_func) for event_id, e in enumerate(events): if 'disable' in e.properties: @@ -48,8 +56,9 @@ def generate(events, backend, group): out('probe %(probeprefix)s.simpletrace.%(name)s = %(probeprefix)s.%(name)s ?', '{', - ' id = simple_trace_map_event("%(name)s")', + ' id = %(map_func)s("%(name)s")', probeprefix=probeprefix(), + map_func=map_func, name=e.name) # Calculate record size
The simpletrace compatibility code for systemtap creates a function and some global variables for mapping to event ID numbers. We generate multiple -simpletrace.stp files though, one per target and systemtap considers functions & variables to be globally scoped, not per file. So if trying to use the simpletrace compat probes, systemtap will complain: # stap -e 'probe qemu.system.arm.simpletrace.visit_type_str { print( "hello")}' semantic error: conflicting global variables: identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-aarch64-simpletrace.stp:3:8 source: global event_name_to_id_map ^ identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:3:8 source: global event_name_to_id_map ^ WARNING: cross-file global variable reference to identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:3:8 from: identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-aarch64-simpletrace.stp:8:21 source: if (!([name] in event_name_to_id_map)) { ^ WARNING: cross-file global variable reference to identifier 'event_next_id' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:4:8 from: identifier 'event_next_id' at :9:38 source: event_name_to_id_map[name] = event_next_id ^ We already have a string used to prefix probe names, so just replace '.' with '_' to get a function / variable name prefix Signed-off-by: Daniel P. Berrange <berrange@redhat.com> --- scripts/tracetool/format/simpletrace_stap.py | 29 ++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-)